Piston skirt knurling tool



July 19, 1960 W. H. MOORE ETA]- PISTON SKIRT KNURLING TOOL Filed May 6, 1957 Fig./

2 Sheets-Sheet 1 William H. Moore Herbert L. Gerald INVENTORS,

r4 1 r Attorneys F mi PISTON sr LING TOOL WilliamiHt Moore, Box 991,.Borger, Tex., and Herbert Gerald", Box 1177, Plainview, Tex.

Filed May-6,-1957,- Ser. No. 657,408 s Claims; e1. so -:1

This invention" relates in general to new'and useful improvements in knurling devices and more specifically toan improvedknurling tool for use. in conjunction with piston skirts. V

During. the operation of an intemaicombustion engine; the. pistons thereof. wear andbecome' distored' with the result that thenormal fit of the pistonswithin" the cylinders is lost. The failure of the piston to properly fit the cylinderresults in an inefficient operationof theintern'al combustion engine. On the other hand,lit is undesirable to replace the pistons because of'thecost of new pistons.

constraction whereby the average garage owner can afford to own one.

'Arit'ither object of'this invention is t'o-p'r'ovide'a knurling tool for piston skirts, the. knurlin tool Bein ortable and being of'sucha nature whereby it may be" readily set upfor us'e'on a worlcbench or other work plac'eandwhich will be of such a nature whereby it ma be readily stored in an out-ofathe-way position when not in use.

Still another object of this invention is to provide an improved. piston skirt knurli'ng tool, the knurling tool being of such a construction whereby pistbns'of all sizes and s h'a'pes-may beeasily mounted therein and effectively knurled by hand with a minimum of elapsed time.

A further. object of this invention is to provide an imroves k'n'u'rlin'g. tool for knurling piston skirts, the knurling oelbeing of a simple and" economical construction and at the same time being of an accurate construction whereby a piston may be accurately mounted therein and properly" knurled;

(Ih'ese together with other objects and advantages which will become subsequently apparent reside in the details of! construction and operation as more fully hereinafter described and. claimed, reference being had to the accompanyingdr'awings forming apart hereof, wherein like numerals refer to like parts throughout, and-in which:

Figure 1 is an elevational' View of the piston skirt knurling tool, which is the subject of this invention, and shows a piston mounted therein and in the process of having the skirt thereof knurled;

Figure 2 is a transverse vertical sectional view taken substantially upon the plane indicated. by the section line 2--2 of Figure l and shows the relationship between Therefore, in the past there has been developed knurling. machines which will effectively raise the surface'of the Patented July 1%, @960 the piston and the knurling tool during the knurling operation, limits of the knurling head during a knurling operation being shown by dotted lines;

Figure 3is'a plan view of the knurling tool ofFigure 1 and shows'further the details of construction thereof;

Figure 4 is a longitudinal sectional view taken through the knurling tool and shows the specific details of the clamping members of the knurling tool for clamping'a piston in. axial alignment'with' the shaft of the knurling tool;

Figure 5 is an enlarged fragmentary vertical sectional View taken substantially upon the plane indicated by the sectionline' f'5 of Figure. Zand shows the specific details ofa knurling head of the tool; and

Figure 6 is a fragmentarytransverse vertical sectional view taken substantially uponthe plane indicatedby the section line 6-6 of'Figure l and'shows the specific detailsof one of the piston clamping members, which .pistori clamping member engages the skirt portion of a piston and which has an opening permitting passage of a connectingirod;

Referringnow to the drawings in detail, it will be seen that there is illustrated a piston skirt knurling tool, the knu'rling tool being referred to in general by the reference numeral 10. The knurling tool 10 includes the first piston clamping member 12. and a second piston clamping member 314 which aretdisposed in spaced relation and which have engageable therebetween apiston 16 which is to be knurled.

The" piston clamping member22 is in the form of a hat plate whose outline is best illustrated in Figure 2. The piston clamping. memberIZ includes a protecting lower' p'ortionli? which is intended to be mounted in a vise or other suitable support. The piston clamping member 12 forms a. main support for the entire piston skirt knu'rling'tool 10.

The piston clamping member 12 has secured to that face'there'of which opposes the piston clamping member 14 a pairof nut' members 20. The nut memherslll are secured to ear portions 22 of the piston clampingmeinber 12 and has threadedly engaged therein spacedparallel'rods' 24.

The piston clamping member 14 includes a plate portion 26 which has the configuration best illustrated in Figure 6. The plate portion 26 includes a pair of cars 28which are aligned with the ear portions 22. The cars 28' carry sleeves 39. on opposite sides thereof through which pass the shafts 24. The ends of the shafts 24 are threaded as at 32' and have received thereon wing nuts 34. The wing nuts- 3'4 serve to maintain the desired relationship between the piston clamping members 12. and 14. 1 7

Referring now to Figure 4 in particular, it will be seenthat the piston clamping member 12 is provided with a bore 36 therethrough. The bore 36 has received therein a reduced portion 38 of a shaft 40. The shaft 40 extends from. the piston clamping member 12 in a direction opposite from the piston clamping member 14.

As is best illustrated in Figure4, the plate portionlti of the piston clamping member 14 is also provided with a bore 42; The bore 42 is aligned With the bore 36 and has received therein an elongated reduced end por tion 44 of a shaft 46. The shaft 46 extends from thepistonclamping member 14 in adirection opposite from thershaft 40 and is coaxial therewith.

The piston 16 is of a conventional type and includes. atop wall 48, a skirt 50 and a piston pin 52. Carried by the piston pin 52 is a connecting rod 54 which extends out through the open lower end of the skirt 50. The head 48 of most pistons are fiat and. are provided with a centering: recess 56. In orderthat the piston 16 may 3 be centered with respect to the shaft 40, the shaft 40 is provided with a coaxial bore 58 in which there is mounted an aligning pin 60. The aligning pin 60 is urged out from the shaft 40 by means of a spring 62 disposed within the bore 58. The aligning pin 60 has aconical end 64 which is receivable in the recess 56.

The piston clamping member 14 also includes a skirt engaging portion 66 which is separate from the plate 26. The skirt engaging portion 66 is provided with a central bore 68 on which there is received that part of the end portion 44 which projects through the plate 26. The

skirt engaging portion 66 is removable from the shaft 46 and is reversible for accommodating pistons of varying sizes. The skirt engaging portion 66 includes a first conical end portion 72 and a second conical end portion 74. The conical end portion 74 is of a larger size than the conical end portion 72. As a result, the conical end portion 72 is engaged in the skirt 50 of smaller pistons 16 whereas the conical end portions 74 is engaged in the skirt of pistons larger than the piston 16.

When it is desired to mount a piston, such as piston 16, within the piston skirt knurling tool 10, the wing nuts 34 are backed off and the piston clamping member 14 moves away from the piston clamping member 12 along the rods of shafts 24-. A piston, such as the piston '16, is then positioned between the piston clamping members 12 and 14 with the piston having the top Wall thereof engaged with the piston clamping member 12 and aligned relative thereto by means of the pin 60. The piston clamping member 14 is then slid along the rods 24 so that the skirt engaging portion 66 thereof is engaged with the skirt of the piston. By tightening down upon the wing nuts 34, it will be seen that the piston to be knurled may be accurately and firmly clamped Within the piston skirt knurling tool 10. e

In many instances it is undesirable to remove the piston rod 54 from the piston, such as the piston 16. Ac.- cordingly, the plate 26 and the skirt engaging portion 66 of the piston clamping member 16 are provided with aligned recesses 76 and 78, respectively. The recesses 76 and 78 are of such a nature whereby they permit the connecting rod 54 to remain on the piston 16 and the piston 16 is clamped between the piston clamping members 12 and 14.

At this time, it is pointed out that all pistons are not provided with flat top walls, such as the top wall 48. In certain instances the pistons are the pop-up type and it will be necessary to provide a special adapter for aligning those pistons with the shaft 40. Also, on rare occasions pistons are made whereby the skirt engaging portions 66 will not properly seat for aligning the skirt and the piston with the shaft 46. If such a piston is to be mounted in the piston skirt knurling tool 10, other adapters will be required in lieu of the piston engaging portion 66.

Mounted on the shafts 40 and 46 is a carrier which is referred to in general by the reference numeral 80. The carrier is generally of a U-shaped configuration and includes an elongated central portion 82 and depending legs 84. The legs 84 are provided with aligned bushings 86 which are mounted on the shafts 40 and 46. The bushings 86 permit the carriage 88 to be both rotated and slid relative to the shafts 40 and 46.

Carried by the carrier 80 is a knurling head which is referred to in general by the reference numeral 88. The knurling head 88 is mounted on the elongated central portion 82 and includes a sleeve 90 which is fixedly secured to the central portion 82. The sleeve 90 has slidably mounted therein a support 92 which is constructed at one end with a pair of spaced ears 94 carrying a pin 96 on which there is journaled for rotation a knurling wheel 98. The support 92 is restrained against rotation within'the sleeve 90 by means of a small rod 100 which has an end thereof received in abore 102 in the central portion 82.

The sleeve 90 is relatively long and is provided with a skirt 50. Therefore, in order that this knurling will be uniformly stopped, there is provided a pair of stop members 114. The stop members 114 are carried by a piston clamping member 12 and are secured thereon by means of bolts 116. The bolts .116 pass through the stop 114 and are threadedly engaged into the piston clamping member 12.

As is best shown in Figure 2, the stops 114 are provided with notched ends 118. The notched ends 118 present notches which are disposed at varying distances from the center of the bolts 116. Thus by pivoting the stops 114, the notches of the notch pins 118 may be so aligned with the central portion 82 of the carrier 80 so as to permit seating of the central portion 82 in respective notches of the stops 114. a

After the piston, such as the piston 16, has been properly mounted in the knurling tool 10, the knurling head adjusted so that the knurling wheel 98 lightly engages the piston 16, the stops 114 are set by swinging the knurling head 88 to opposite ends of its travel and engaging the central portion of the carriage 80 with the stops 114, such as shown by the dotted line positions of the knurling head 88 in Figure 2. Once the stops 114 have been set,

the knurling wheel 98 is engaged with the lower part of the skirt 50, as is best shown in Figure l. The knurling wheel 98 having been properly adjusted with respect to the piston 16, the carrier 80 is swung about the shafts 40 and 46 so as to perform a knurling operation on the desired portions of the skirt 50. As each knurling sequence is accomplished, the knurling head 88 is released and the carrier 80 slid along the shafts 40 and 46 so as to align the knurling wheel 98 with the next unknurled portion of the skirt 50. The process is repeated until the desired portion of one-half of the skirt 50 is knurled. At this time, the wing nuts 34 are backed oif slightly and the piston 16 rotated 180. The wing nuts 34 are then again tightened and the knurling process continued so that both halves of the skirt 50 of the piston 16 may be knurled.

From the foregoing description of the knurling tool 10,

it will be readily apparent that there has been provided a knurling tool which is relatively simple andmay be economically constructed so that owners of small-garages may afford it. Also, the tool is of such a nature whereby no special fixture is required, the tool being readily mounted in a vise or other similar support. Despite the fact that the tool is very simple, it will also be apparent that the knurling operation may be that desired and thus may be accomplished by the average garage owner utilizing the tool 10.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A knurling tool for pistons, said knurling tool comprising a pair of opposed piston clamping members for supporting a piston in position for knurling, means adjusta'bly urging said piston clamping members into piston clamping relation, aligned shafts extending inopposite directions from said piston clamping members, a

carrier, said carrier bridging the space between said piston clamping members and having end portions journaled on said shafts for rotational and longitudinal movement, a knurling head, and means connected to said knurling head mounting said knurling head on said carrier for rotational and longitudinal movement relative to a piston being knurled, one of said piston clamping members having an extension receivable in a support structure, such as a vise, whereby the knurling tool may be readily supported.

2. A knurling tool for pistons, said knurling tool comprising a pair of opposed piston clamping members for supporting a piston in position for knurling, means adjustably urging said piston clamping members into piston clamping relation, aligned shafts extending in opposite directions from said piston clamping members, a carrier, said carrier bridging the space between said piston clamping members and having end portions journaled on said shafts for rotational and longitudinal movement, a knurling head, and means connected to said knurling head mounting said knurling head on said carrier for rotational and longitudinal movement relative to a piston being knurled, stop members mounted on one of said piston clamping members for engagement by said carrier to limit movement of said knurling head about a piston.

3. A knurling tool for pistons, said knurling tool comprising a pair of opposed piston clamping members for supporting a piston in position for knurling, means adjustably urging said piston clamping members into piston clam-ping relation, aligned shafts extending in opposite directions from said piston clamping members, a carrier, said carrier bridging the space between said piston clamping members and having end portions journalled on said shafts for rotational and longitudinal movement, a knurling head, and means connected to said knurling head mounting said knurling head on said carrier for rotational and longitudinal movement relative to a piston being knurled, stop members mounted on one of said piston clamping members for engagement by said carrier to limit movement of said knurling head about a piston, each of said stop members being in the form of an elongated arm, a combination pivoted clamping member securing one end of said arm to said one piston clamping member, the opposite end of said arm being in the form of a plurality of stop forming shoulders spaced different distances from said pivot and clamping member.

References Cited in the file of this patent UNITED STATES PATENTS 113,959 Wood Apr. 18, 1871 290,612 Tucker Dec. 18, 1883 857,242 Johnson June 18, 1907 1,494,244 Hoagland May 13, 1924 2,619,708 Neal Dec. 2, 1952 2,635,491 Bell et al. Apr. 21, 1953 2,677,977 Phillips May 11, 1954 2,717,525 Phillips Sept. 13, 1955 2,798,390 Bennett July 9, 1957 

